Hybrid polymers comprising units, e.g., of the type EQU {--Me.sub.2 SiC.sub.6 H.sub.12 SiMe.sub.2 O--} (i)
wherein Me hereinafter denotes a methyl radical, are known in the art. Their preparation generally includes the following steps: A silane is prepared according to chemical equation (1): EQU Me.sub.2 SiH.sub.2 +Me.sub.2 SiCl.sub.2 .fwdarw.2 Me.sub.2 Si(Cl)H(1)
wherein the reaction is carried out in the presence of, e.g, tetraisobutylammonium bromide. The product of this reaction is then reacted in a hydrosilation reaction to endcap a vinyl or allyl-terminated compound, as represented by equation (2): EQU 2 Me.sub.2 Si(Cl)H+CH.sub.2 .dbd.CHC.sub.2 H.sub.4 CH.dbd.CH.fwdarw.ClMe.sub.2 SiC.sub.6 H.sub.12 SiMe.sub.2 Cl(2)
in which the reaction is carried out in the presence of a platinum catalyst. The resultant chlorine-terminated compound is then hydrolyzed and condensed to form the corresponding hybrid sila-organo-siloxane polymer (i). Of course, the above hydrolysis can also be accomplished in the presence of another diorganodichlorosilane and these mixtures may be condensed to provide copolymers. It has been observed that, even though the reaction represented by equation (2) is relatively efficient (yield is in the range of 80 to 90%), the reaction according to equation (1) is relatively inefficient (yields observed are only in the 40% to 60% range). The overall yield for the formation of the hydrolysis products is therefore in the general range of 32 to 54%. And, since the polymers and copolymers produced from these hydrolyzates have utility in such diverse applications as lubricants, rubbers and sealants, there is motivation to improve the process for their manufacture.